Apparatus for spray drying



June l, w3? w, s. BOWEN v 2,08L309 APPARATUS FOR snm DRYING Filed Nov. 2o, 1934 INVENTOR:

u BY #v7/M, )hun f W ,HIS AT DRNEYS hl'apuynencerwren,

Patented June 1, 1931 V UNITEDSTATl-:s PME-N1#l OFFICE l William Spencer Bowen,

Application November zo, 1934, serial No. 153,851

westneia, N. J. I

13 claims. (ci. 15s- 4) The invention embodies improved apparatus and processes for carryingv out `operations by means of which substances may be treated in such fashion as to, be eifectively homogenized or spray dried.

An object of the invention is to provide an improved process and apparatus wherein a rotating l fluid wall is maintained within the drying chamber inwardly Qf/"the periphery thereof. in such fashion as to avoid the accumulation of products upon the walls of the chamber.

A further object of the invention, accordingly, is to provide a method and apparatus by means of which uids may be treated by an improved recirculating system including the provision of a rotating air curtain or wall formed by a recirculated iiuid. In this connection, it is to be noted that the system contemplates the substantial drying of products sprayed into the dryingchamber prior to contact vthereof with the recirculated fluid which is directed into the drying chamber in the form of a curtain or rotating uid wall, this being effected by spacing the rotating curtain or wall from the spraying mechanism.

A. further object of the invention is to provide an improved drying mechanism by means of which a medium may be recirculated to form an effective rotating -wall or curtain adjacent the interior surface of the drying chamber and spaced from the spraying mechanism. In this connection, the drying device is preferably formed with a manifold and vertical nozzles which are properly oriented in spaced relationship about the walls of the chamber.

A further object of the invention is to provide an apparatus and process by means of which complete recovery of all dried particles is effected prior to the iinal exhaust of the fluid in which the particles are suspended, the heat values in the last named fluid being substantially removed therefrom to eifect preheating and carbonating of the substance to be treated.

- Further objects, not speciiically enumerated above, will be apparent as the invention is described-in greater detail in connection vwith the accompanying drawing, wherein:

Figure 1v is an enlarged view in section of the 3-3 of Figure 2, and looking in the direction of `the arrows. v

Figure 2 is a horizontal view in section, taken` on the line 4-4 of Figure 1, and looking in the direction of the arrows.

Figure 311s a detail view showing the structure of the spray head shown in Figure .1.

a With reference to- Figure 1, the apparatus will befseen to -include a drying mechanism indicated at I0 with which a fan I I, is associated to facilitate the flow of a medium therethrough. A conduit I2 provides communication between an exhaust manifold I3 of the drying mechanism and the suction side of the fan. From the' fan II, fluid with particles in suspension is directed through a pipe I4 to one or more dust collectors I5 which may be of any well known design. The solid particles recovered from the collectors I5 may be directed to receiving mechanism, not shown, and a portion of the exhaust from the collectors maybe returned to the drying chamber through a pipe line I1-.

With reference to Figures 1 and 2, the substance tobe dried is introduced into the drying chamcateswith the interior of the head 41 and isdirected downwardly thereof. In chamber 48 is 49 about which a suitable screw or through the chamber 48 received a valve stem thread 50 is formed in order that the fluid may be subjected to a whirling motion prior to being discharged from the spray head. The lower portion of the stem 49 carries a valve plate' 5I which is adapted to be moved against a valve seat 52 formed upon the bottom of the head 41. The position of the valve plate 5I with respect to the-seat 52 may be varied by means of a nut 53, or other suitable means by which the stem may be turned in its thread 54.

A drying medium is directed through a pipe 56y into a discharge member 51 centrally of the drying chamber I0. The discharge member is formed with a converging outlet 58 which is positioned about the spray head 41 in order that the drying medium may be directed downwardly against the spray of substance discharged from the head. The drying chamber is formed with an outlet manifold I3 above referred to which is positioned substantially flush with the iioor 59 of the drying chamber. Apertures 60 are formed in the walls of the drying chamber in order that the outlet manifold I3 may communicate therewith.

In order that a portion of the exhaust from the drying mechanism may be recirculated therethrough, the fan Ilfis provided with la second outlet communicatingwith a pipe 6I. Pipe 6I communicates with an upper manifold 62 about the exterior of the drying chamber, the manifold being formed with 4.downwardly extending chambers 63 whichl may terminate adjacent lthe outlet manifold I3. Each chamber `63 is formed with an elongated nozzle 64 which directs fluid. therefrom at an angle with respect to the radius of the drying chamber. In the form shown the nozzle $4 directs fluid therefrom at an angle of substantially 45 with respect to radii of the drying chamber as indicated by the dot and dash arrows in Figure 2. A series of horizontal rectifying plates 65 is provided in each of the nozzles 64 in order that the ow of uid discharged from the nozzle may be ln horizontal planes. In this fashion, the vertical nozzles 54 form a rotating curtain or wall of fluid which is spaced from the spray head 41 and thus serves to pick up the substance in the chamber and subject it to an effective drying and treating operation.

If desired, the drying chamber may be provided with a rotatable hollow sweeper 6%, receiving a portion of the discharge from the collectors l5 through pipe l?. The construction of this sweeper may be in accordance with the structure shown in my Patent No. 1,946,566.

I claim as my invention:

l. A drying mechanism comprising a chamber forming means, means at the top of the chamber and adjacent the axis thereof to introduce a substance to be dried, means to introduce a drying medium into the chamber adjacent the last named means, means to remove the substance and medium from adjacent the bottom of the container, and means to introduce a plurality of iiuid streams into the chamber at the side thereof at angles to radii from the axis of the chamber and to tangents to said radii to form a rotating uid wall therein.

3. A drying mechanism comprising a chamber forming means, means at the top of the chamber and adjacent the axis thereof to introduce a sub- 4. A drying mechanism comprising a chamber forming means, means at the top of the chamber with a drying medium plurality of uid streams therein, and means to direct-removed dried substance and medium to the nozzles.

top of the chamber communicating with the nozzles, and means to direct removed dried substance and medium to the nozzles.

6. The process of spray drying comprising introducing a substance to be dried into a chamber with a removing the dried substance 7. The process of spray drying comprising introducing a substance to be dried into a chamber 9. A drying mechanism comprising a chamber forming means, means at the top of the chamber axis of the chamber which rotates in the direction of whirl of the substance to be dried.

adjacent the bottom of the chamber, and means spaced from the chamber wall and wim-1mg m to introduce a fluid into the chamber at the side the direction of whirl of the substance m be thereof at an ansie to a tangent to the chamber dried. at the point at which the last named iluid is 12. The process of spray drying comprising in- 5 introduced andl in the direction of whirl of the troducing a substance to be dried into a chamber, 5 substance to be dried. the anguiarity of the introducing a drying medium therein with a direction of motion of the last named iluid being whirling motion, removing the dried substance such as to form a rotating curtain of iluid spaced and medium, and forming a iluid wall oi a porrom the chamber wall and whirling in the direction oi' the dried substance and medium adjacent 10 tion of whirl of the substance to be dried. the wall of the chamber moving in .the direction 10 il. A drying mechanism comprising a chamof whirl of the substance to be dried. y ber forming means, means at the top of the 13. A drying mechanism comprising a chamchamber and adjacent the axis thereof to introber forming means, means to remove a substance duce a substance to be dried into the chamber to be dried and a treating medium from adjacent i5 with a whirling motion about the axis of the the bottom of the chamber forming means. qs

chamber, means to remove the substance and means to introduce a plurality of fluid streams medium from adjacent the bottom of the chamof a treating medium into the chamber forming ber. and means extending axially of the chammeans at the sides thereof at angles to radii trom ber to introduce a fluid into the chamber at the the axis of the chamber forming means and to 20 side thereof at an angle to a tangent to the i tangents to said radii to form a rotating fluid 2o chamber at the point at which the last named wall therein, and means to introduce a substance rluid is introduced and inthe direction of whirl to be dried into the chamber forming means inoi the substance to be dried, the angularity of wardly of the rotatinguld wall.

. the direction of motion oi the last named huid 25 being auch as to form a rotating curtain of huid WILLIAM SPENCER. BOWEN. 25 

